/*
 * main program to drive CCITT Group 4 decompression
 */

#include "g4codec.h"
#include <memory.h>
#include <io.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

 #define _BYTE_ASCII

#ifdef _BYTE_ASCII
#define _BYTE_ZERO 0x30
#define _BYTE_ONE 0x31
#else
#define _BYTE_ZERO 0x00 // _BYTE_BINARY
#define _BYTE_ONE 0x01 // _BYTE_BINARY
#endif

/*
 * This Program extracts a compressed image from the file pointer passed,
 * stripping the file header and loads it into memory.  It gets the
 * dimensions of the resultant pixrect image from the compressed header
 * and allocates the pixrect structure. It reverses the bits in the
 * compressed image and calls decompress4() for decompression.  The 
 * pixrect structure is used so the image can be displayed.
 */

int convertFromByte(char *inData, char *outData, int total, int width, int height)
{
	int in, out, maxOut;
	char outByte;
	int inVal;

	maxOut = width * height;
	outByte = 0;
	out = 0;
	for (in=0; in<total, out<maxOut; in++)
	{
		inVal = inData[in];
		switch(inVal)
		{
		case _BYTE_ZERO: // 0
			outByte = outByte<<1;
			out ++;
			if ((out % 8) == 0)
			{
				outData[(out/8)-1] = outByte;
				outByte = 0;
			}
			break;
		case _BYTE_ONE: // 1
			outByte = (outByte<<1) + 1;
			out ++;
			if ((out % 8) == 0)
			{
				outData[(out/8)-1] = outByte;
				outByte = 0;
			}
			break;
		default: // don't care
			break;
		}
	}
	if ((out % 8) != 0)
	{
		outData[out/8] = outByte; // flush
		return (out/8+1);
	} else
	{
		return (out/8);
	}
}

int main(int argc, char* argv[])
{
	u_char	*source;	/* Pointer to compressed image in memory */
	u_char	*destination;	/* Pointer to decompressed raster in memory */
	char	*infile;	/* Pointer to compressed name (argv[1]) */
	char	*outfile;	/* Pointer to uncompressed name (argv[2]) */
	FILE	*input;		/* Compressed file pointer */
	FILE	*output;	/* Decompressed file pointer */
	int		height;		/* Raster image height in pixels */
	int		width;		/* Raster image width in pixels */
	u_int	filesize;	/* Size of compressed image in bytes */
	int		outbytes;	/* Output length */
	int		iCodec;

	if(argc < 6)
	{
		fprintf(stderr,	"Usage: %s codec(0/1/2) srcFile destFile width height\n",
				argv[0]);
		fprintf(stderr,	"Flag: 0 decode, 1 compress 1BPP, 2 compress 8BPP\n");
		exit(-1);
	}

	iCodec = atoi(argv[1]); // 0 for decode, 1 for comp binary, 2 for comp byte
	infile = argv[2];
	outfile = argv[3];
	width = atoi(argv[4]);
	height = atoi(argv[5]);

	/*
	 * Open input
	 */
	if ((input = fopen(infile,"rb")) == NULL)
	{
		fprintf(stderr,"%s: Can't open %s\n",argv[0], infile);
		exit(-2);
	}

	/*
	 * Open output
	 */
	if ((output = fopen(outfile,"wb")) == NULL)
	{
		fprintf(stderr, "%s: Can't open %s\n", argv[0], outfile);
		exit(-3);
	}
	
	// find out input size
	
	if (iCodec == 1) // encoding binary, file can be larger than image
	{
		filesize = width*height/8;
		if ((width*height%8) != 0)
			filesize ++;
	} else
	{ // in other case we don't know the real size of input
		filesize = _lseek(_fileno(input), 0L, SEEK_END); // seek to EOF
	}

	if( (source = (u_char *) malloc(filesize)) == NULL)
	{
		fprintf(stderr, "%s: Can't malloc %d bytes for %s.\n",
				argv[0], filesize,infile);
		exit(-4);
	}

	_lseek(_fileno(input), 62L, SEEK_SET); // seek to Beginning of file

	/*
	 * Read input image
	 */
	if (fread(source, 1, filesize, input) != filesize)
	{
		fprintf(stderr, "%s: Error reading compressed file.\n", argv[0]);
		exit(-6);
	}
	fclose(input);
	// maximum size of destination, assuming binary image
	destination = (u_char *) malloc(2*width*height/8);
	if ( destination == NULL)
	{
		fprintf(stderr, "%s: Destination_create failed.\n",argv[0]);
		exit(-5);
	}

	// special treatment to covert from byte per pixel to bit per pixel
	if (iCodec == 2)
	{
		outbytes = convertFromByte(source, destination, filesize, width, height);
		if (outbytes != width*height/8)
			exit (-7);
		else // store the raw data back at the source
			memcpy(source, destination, outbytes);
		filesize = outbytes;
	}

	// perform codec
	if (iCodec == 0)
	{
		grp4decomp(source,filesize, width,height, destination, &outbytes);
	} else
	{
		grp4comp(source,filesize, width,height, destination, &outbytes);
	}

	// the output as pbm for decoded image
	if (iCodec == 0)
		fprintf(output, "P4\n%d %d\n", width, height);

	fwrite(destination, outbytes, 1, output);
	fclose(output);
}